Over the past few weeks, few types of investments have shone as bright as gold. Fueled by a wobbling stock market and concerns over the European debt crisis, gold prices have eclipsed $1,200 per ounce, and many believe they could continue to climb. "Gold is the quintessential safe-haven play and currency hedge, and that's certainly why gold's been the beneficiary of any concerns or fears," says Dave Meger, the director of metals trading at Vision Financial Markets.

Still, there are plenty of things that could derail the yellow metal's blistering rally. Gold, which thrives when investors are fearful, tends to stall or sink when markets are strong or when crises settle down. Gold, however, is hardly the only precious metal out there. With that in mind, here's a guide to how three other metals -- platinum, palladium, and silver -- fit into investors' portfolios.

Platinum and palladium.

Even as gold prices surged this month, platinum and palladium have struggled to find their footing. That's because more so than gold, these two "white metals" have a number of industrial applications. Platinum and palladium are particularly common in the automotive industry, where they are used to make catalytic converters. In other words, when the stock market dips -- particularly when the fall affects consumers' demand for cars -- platinum and palladium will often lose out.

As a result, prices on the two metals tanked when the combination of the May 6 flash crash and the European debt crisis weighed on global markets. Still, there are signs that this pattern could reverse itself. For instance, when markets rallied on Thursday, the two metals shot up, with New York spot palladium gaining 6 percent in the course of a single day. "I think the global risk markets -- the equities, the oils, those sorts of things -- have all overpriced the risk from financial regulation and from European debt default," says Tom Pawlicki, a commodities analyst with MF Global. "In that regard, I think there can be a recovery in risk markets, a recovery in the euro. That would probably drag on the gold market relative to the other metals."

Despite these differences, platinum, palladium, and gold will often all move in the same direction by virtue of all being precious metals. All three, for instance, have seen sharp gains since late 2008. Year to date, spot prices on platinum have gained 7 percent and those on palladium have tacked on 18 percent. Gold, by comparison, is up 11 percent. Still, experts say that the fact that the white metals can diverge from gold during periods like those the market experienced this month is a reason for gold investors to diversify into platinum and palladium, and vice versa.

Silver.

Like the other precious metals, silver has had a rather impressive streak; New York spot silver has gained upwards of 10 percent this year. In terms of its place in a portfolio, silver falls somewhere between gold, platinum, and palladium. "If we see the continuous [deterioration] in the debt situation in Europe -- not just with Greece, but if we see that in the other regions -- I think that bodes well for gold," says Fred Jheon, ETF Securities' head of product development for the United States. "If we do see some of that easing off and a recovery of the economic cycle, then I think that bodes well for platinum and palladium ... And silver is probably in between the two."

When silver and gold diverge, the difference often signals investors' views toward the economy.

"When they think the economy is going to do well, they'll buy silver and sell gold," says Pawlicki. "When they think the economy
will do poorly or there's a need for a safe haven, they'll buy gold and sell silver." That's because gold is still investors'
favorite among the precious metals when it comes to hedging against crises. "[Silver is] more of a bridesmaid than the bride,"
says Jheon. "So there is some correlation in terms of diversification and inflation ... and currency [hedging], but it's not
as much of a safe-haven asset as gold is."